The dispensing of condiments and other sauces have long been done by the use of hand operated pumps that are controlled by using the force generated by the operator to force product from a cylinder out of a tube to a dispensing nozzle. This action takes place in opposition to a spring that acts to force the pump handle in an outward direction. When the dispensing stroke is finished and the handle released, the previously compressed spring returns the handle to the start position and refills the cylinder by generating a partial vacuum to suck product from a reservoir. The reservoir is typically a crock with a lid where the pump is mounted. The total lift of the product is generally less than 12 inches. This lift as well as other factors like the pump's construction determines the strength of the spring required. This type of dispensing pump is and has been used to dispense not only condiments but other sauces like toppings on desserts, cheese sauce etc.
These pumps are typically required to be cleaned every day as the crevices and small openings become convenient locations for bacterial contamination and product build up. Disassembly of the component parts is sometimes required during the approved cleaning procedure. This process is prone to such difficulties as losing some of the pieces or faulty reassembly of the pump, resulting in premature failure. The mating surfaces of the pump are areas where constant disassembly and reassembly is most likely to cause future problems.
Recently the use of condiments packed in a flexible bag format typically referred to as a "BIG-IN-BOX" has increased. This format has several advantages over traditional packaging formats. Sanitation is the prime motivator for using this type of format. Unfortunately "bag-in-box" condiments have required relatively complicated and expensive systems to dispense the product.
Attempts to use "Hand Pumps" and Bag-In-Box formats together have met with limited success. Most have used existing hand pump designs adapted to pump from a bag. The reason these fail to operate effectively is due to the action of the spring being regulated to pull condiment from the bag after the dispensing stroke is complete. The spring can fill the pump quickly when it is immediately above a crock but will fill slowly when required to pull condiment from a bag at a remote condition only a few feet away. This increase in fill time limits the use of this type of system.
It can be appreciated that there exists a need for a pumping mechanism that can be used to readily pull product from remote locations and quickly refill dispensing chambers. Also it is essential that the mechanism be easily cleaned and sanitized.